package QueueDemo;

import java.util.Stack;

public class MyQueueUseStack {
    public Stack<Integer> stack1;
    public Stack<Integer> stack2;

    public MyQueueUseStack() {
        stack1 = new Stack<>();
        stack2 = new Stack<>();
    }

    public void push(int x) {
        stack1.push(x);
    }

    public int pop() {
        if(empty()){
            return -1;
        }
        if(stack2.empty()){
            int size = stack1.size();
            for (int i = 0; i < size; i++) {
                stack2.push(stack1.pop());
            }
        }
        return stack2.pop();
    }

    public int peek() {
        if(empty()){
            return -1;
        }
        if(stack2.empty()){
            int size = stack1.size();
            for (int i = 0; i < size; i++) {
                stack2.push(stack1.pop());
            }
        }
        return stack2.peek();
    }

    public boolean empty() {
        return stack1.empty() && stack2.empty();
    }
}
